It’s good, Martin. And the technique is well-executed. If I have a question, it would be about how come you’d go to the trouble of balancing ambient and flash in brilliant sunshine if you weren’t going to include some information about the context in the ambient exposure. Not a criticism – just wondering.

For me her face is a bit too light compared with the background. I take it she was lit by direct sunlight and you’ve used the flash to fill-in the shadows? Photographing in harsh sun light is always difficult. I try to turn the subject into their shade and use a bit of flash to give them a lift. It’s not particularly easy to get the balance right.

Well, the truthful answer is I forgot, so lets start afresh. I used Aperture priority mode on my camera and set the aperture to f3.2. ISO was set at 100 and the exposure bias was set at -2 EV. The camera then selects an appropriate shutter speed which was 1/6400. At high shutter speeds you have to set your flash to high speed sync. The flash then sends out enough power for the aperture and the -2 EV darkens the background.

I positioned the model so she had her back to the sun, no squinting and nice rim lighting. I decided on f3.2 because it seemed to work well on previous occasions, focal length was 85mm on a full frame camera.

Its not perfect but I like it and it was a great learning experience and its a technique that I will use in the future.

I should have realised that the lack of a squint meant she wasn’t facing the sun. I think f3.2 works well here as well. It’s an interesting technique that needs using with the attention to detail that you’ve taken. Is there a shutter speed limit when using high speed sync flash? Being lazy I usually set the flash to auto at -1 stop hoping it will act as a fill-in. I set the camera manually so I can control the aperture and shutter speed. It works most of the time. I don’t know about your Canon, but on mine if your using flash and auto ISO the camera will set itself to 400ISO so I set the ISO manually when using flash. Shooting in RAW gets me out of jail, but it’s best to get it right in camera of course.

Overpowering the sun with a DSLR can be tricky, because of the relatively low sync speed. The leaf shutter on the Fuji X100 series cameras can sync up to 1/4000 sec, (plus the cameras have a built-in 3-stop neutral density filter) which means you can completely suppress the ambient light, even at the widest apertures on a very bright day.

In Aperture priority mode all shutter speeds are available if you have selected high speed flash on your speedlite. This is particularly handy for fill flash. I do not know if this is applicable to all canon speedlites.

I was thinking of those situations where you might want to make the background totally black for starters, then set the right flash illumination on the subject using aperture and flash power, and then bring up the background detail by slowing the shutter gradually until just the amount of background detail you want becomes visible. With the native high speed sync that a leaf shutter gives you, this is possible without reducing the power output of the flash, so the ‘reach’ is maintained even for subjects that are more distant from the camera.

The issue with ‘high speed sync’ technology in Canon and Nikon speedlights is that it greatly diminishes the power output. Rather than one big flash “pop,” it pulses at approximately 30,000 times per second to ensure the flash is firing at every point as the shutter travels across the imaging plane, which ordinary flash can’t do above the native sync speed of the camera – usually below 1/200s for a DSLR, as you know. The other downside of ‘high speed sync’ is that the more you increase the shutter speed, the less power output the Speedlite will be able to produce, so you have to keep the subject near the light – the faster the nearer!

Of course, as you imply, this is usually not an issue when you are doing head shots or head & shoulders portaits and all you want is a bit of fill. Full length action shots are another story! 😉